In order to improve the inaccurate diagnosis results caused by extracting opening and closing current feature inaccurately and make up for the deficiency of operating mechanism of circuit breakers defect diagnosis technology in the aspect of severity,a diagnostic method based on the eigenvalues of wavelet packet energy and support vector machine (SVM) as an intelligent algorithm is proposed.Meanwhile,the characteristic data is utilized to explore the trend of the defect.In conclusion,the feasibility of the method is verified through the analysis of the data of the normal operation,the control loop fault and the iron core astringent defects of the circuit breakers.